I thought this was a mostly solid book. The final revelation was certainly a surprise to me.
I think the addition of the new cast member should be interesting. I'm very, very glad she's female and not yet another male for Kara to angst over.
Here's my thing with the Rhyzkahl situation. Why, exactly is she falling for him? He's hot and the sex is great. Okay, fine. He also clearly has no problem terrifying her if she does something he doesn't like. I fail to see what's attractive about a mate who in any other context would be considered abusive. It's what turned me off of Lilith Saintcrow's series. It's not sexy or loving or in any way good when on partner seeks to control the other through fear and/or pain and I really don't understand why we as readers are supposed to root for that relationship or feel anything positive about him. Is it is supposed to be okay because he's hot and great in bed? I'm not at the point yet where I'm going to stop reading the series but much more in that direction and I probably will. (Basically, I liked this book except for the part where she decides she might be falling for Rhyzkahl and thinks he might be feeling affectionate about her without putting that affection in context).
I do think the revelation about Zack was really interesting and I'm particularly looking forward to exploring that in the future. But here's my question, if he can appear and act mostly human is he suddenly no longer bound by the rules and formalities of others of his kind?
Despite my complaints I did like this book I just (obviously) have some major quibbles.